feat: use native preview for pdf in mobile webview (#1728)

packages/mobile/src/Lib/Interface.ts

@@ -14,6 +14,7 @@ import {
   TransferPayload,
 } from '@standardnotes/snjs'
 import { Alert, Linking, PermissionsAndroid, Platform, StatusBar } from 'react-native'
+import FileViewer from 'react-native-file-viewer'
 import FingerprintScanner from 'react-native-fingerprint-scanner'
 import FlagSecure from 'react-native-flag-secure-android'
 import {
@@ -541,7 +542,7 @@ export class MobileDevice implements MobileDeviceInterface {
 
     try {
       const path = this.getFileDestinationPath(filename, saveInTempLocation)
-      void this.deleteFileAtPathIfExists(path)
+      await this.deleteFileAtPathIfExists(path)
       await writeFile(path, base64.replace(/data.*base64,/, ''), 'base64')
       return path
     } catch (error) {
@@ -549,6 +550,28 @@ export class MobileDevice implements MobileDeviceInterface {
     }
   }
 
+  async previewFile(base64: string, filename: string): Promise<boolean> {
+    const tempLocation = await this.downloadBase64AsFile(base64, filename, true)
+
+    if (!tempLocation) {
+      this.consoleLog('Error: Could not download file to preview')
+      return false
+    }
+
+    try {
+      await FileViewer.open(tempLocation, {
+        onDismiss: async () => {
+          await this.deleteFileAtPathIfExists(tempLocation)
+        },
+      })
+    } catch (error) {
+      this.consoleLog(error)
+      return false
+    }
+
+    return true
+  }
+
   confirmAndExit() {
     Alert.alert(
       'Close app',